Due to inertia of motion and inertia of rest,the limiting friction is greater.when the body is at rest then to move it we must exceed the inertia of rest as well as frictional force but when the body comes in motion then due to inertia of motion we require to give less force to overcome friction.so,in this case limiting reaction is greater.

Alternative is,when the body is at rest then the interlocking between the surface is greater and we have to apply more force but when the body is at motion then there is less time to be interlocked.so,we have to apply less force.Due to this limiting friction is greater than dynamic friction.